[PATCH] D26123: Fix SegFault in Expected

[Yichao Yu via llvm-commits]

yuyichao created this revision.
yuyichao added a reviewer: lhames.
yuyichao added a subscriber: llvm-commits.

The placement new on getErrorStorage() is of the wrong type.

AFAICT this is the intent in https://reviews.llvm.org/rL265446 which somehow starts to trigger a segfault when the destructor of the unique_ptr is called after https://reviews.llvm.org/rL285426. Ref https://github.com/JuliaLang/julia/issues/19154


https://reviews.llvm.org/D26123

Files:
  include/llvm/Support/Error.h


Index: include/llvm/Support/Error.h
===================================================================
--- include/llvm/Support/Error.h
+++ include/llvm/Support/Error.h
@@ -147,7 +147,7 @@
 
   // Expected<T> needs to be able to steal the payload when constructed from an
   // error.
-  template <typename T> class Expected;
+  template <typename T> friend class Expected;
 
 public:
   /// Create a success value. Prefer using 'Error::success()' for readability
@@ -642,7 +642,7 @@
 
   {
     assert(Err && "Cannot create Expected<T> from Error success value.");
-    new (getErrorStorage()) Error(std::move(Err));
+    new (getErrorStorage()) error_type(Err.takePayload());
   }
 
   /// Create an Expected<T> success value from the given OtherT value, which


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